Heteropolysaccharide produced by Pseudomonas sp

ABSTRACT

The present invention relates to a heteropolysaccharide (HP) characterized in that it can be obtained by fermentation of a medium comprising at least one strain of Pseudomonas sp I-2054 (or DSM 12295), one of the recombinants thereof or the mutants thereof and a source of carbon which can be assimilated by said strain, one of the recombinants thereof or one of the mutants thereof. The invention also relates to a method for the production and use of said heteropolysaccharide as a thickening agent and/or gelling agent.

The present invention relates to a novel heteropolysaccharide (HP), to aprocess for preparing it by fermenting a Pseudomonas sp I-2054 (or DSM12295) strain, to said strain, and to the uses of thisheteropolysaccharide as a thickener and/or gelling agent.

In many fields of industry, they are constantly on the lookout for newcompounds which feature:

improved rheological properties and are capable of forming gels,

increased compatibility with the media in which they are incorporated,

great stability within a wide temperature and pH range.

In the case of compounds obtained at the outcome of a bacterialfermentation, it is also important for the compound to have goodproductivity.

The capacity to gel is of great interest, since such systems areparticularly attractive owing to the diversity of fields in which theyfind applications: some applications require the use of a gel.

Thus, for example, agribusiness provides a wide range of gel products(cream desserts, yogurts, various jellies, ices, etc.), and thepharmaceutical industry uses gels as vehicles for active principles oras thickeners.

In a quite different field, some paints do not drip by virtue of thefact that they possess gel characteristics at rest, whereas they spreadeasily under the action of the brush (shear-thinning profile).

Aqueous gels are also used as chromatographic supports or else for thedevelopment of contact lenses.

Heteropolysaccharides of bacterial origin such as xanthan gum, forexample, have already been described and used for their effectiverheological properties under extreme temperature and pH conditions.However, these heteropolysaccharides, which are suitable in applicationsin solution, do not always produce gels.

It is known that the gelling of a medium takes place when athree-dimensional network is formed subsequent to the crosslinking ofthe components of said medium.

Conventionally, this gelling is brought about by adding additionalcations to the medium, especially cations of the alkali metal oralkaline earth metal type (for example calcium and/or magnesium), byswitching the pH toward acidic or basic values, by adding anothercompound, in particular another polysaccharide (for example, thecombination of xanthan and carob), or by altering the temperature.

Whatever the application envisaged, the abovementioned gellingconditions may:

harm the stability and the compatibility of the final gel, owing tointeractions between the additional cations or the coadditive, whichmust be introduced in order to obtain the gel, and the other ingredientspresent in said compositions, or

denature the heteropolysaccharide and/or the other ingredients presentin said compositions, owing to high temperatures and/or changes in pH.

In the context of the present invention, a “gel” denotes a pseudo-solid(behaving very similarly to a solid) resulting from the at least partialassociation of heteropolysaccharide chains dispersed in a liquid. Withina stressing frequency range ω, the pseudo-solid gels are generallycharacterized, with regard to their solid component, by an elasticmodulus G′(ω), also called storage modulus, and, with regard to theirliquid or viscous component, by a viscous modulus G″(ω), also calledloss modulus.

The mechanical values G′(ω) and G″(ω) may be measured using a controlledstrain rheometer which operates in oscillatory mode. By way ofnonlimiting indication, mention may be made, for example, of aRheo-Fluid Spectrometer® rheometer.

G′ and G″ may also be measured on a controlled stress rheometeroperating in oscillatory mode. By way of indication, mention may bemade, for example, of a CARRIMED® rheometer.

The principle of the measurement consists in determining, firstly, therange of reversible mechanical strain in which the response of the gelto mechanical stress is linear as a function of said strain. Secondly,the gel is subjected to a set value of mechanical strain containedwithin the linear range determined beforehand. The rheometer thencarries out a frequency sweep ω.

The stress response of the gel which is in phase with the strain givesaccess to the elastic modulus G′(ω). G′(ω) corresponds to the energystored by the gel in elastic form, and is recoverable.

The stress response of the gel which is out of phase by an angle of 90°with the strain gives access to the viscous modulus G″(ω). G″(ω)corresponds to the energy dissipated by the viscous flow, and isirrecoverable.

A gel is said to be strong or true when, throughout the stress frequencyrange (ω) swept, the G′/G″ ratio is greater than or equal to 10, i.e.,when the elasticity of the gel remains high and when the value of G′(ω)is greater than or equal to 10 Pa.

A specific aim of the present invention is to provideheteropolysaccharides which possess very good rheological properties,especially in terms of thickening and pseudoplastic (shear-thinning)properties, and also the capacity to give true gels without the additionof additional cations to the medium and without pH switching, and to doso at temperatures less than or equal to 40° C.

Another aim of the present invention is to provide aheteropolysaccharide having very good rheological properties at lowconcentrations.

The present invention first provides a heteropolysaccharide (HP)characterized in that it is obtainable by fermenting a medium comprisingat least one Pseudomonas sp I-2054 (or DSM 12295) strain, one of itsrecombinants, or one of its mutants, and a carbon source assimilable bysaid strain, one of its recombinants, or one of its mutants.

The Pseudomonas sp strain was deposited in accordance with the Treaty ofBudapest at the Collection Nationale de Culture des Micro-organismes(CNCM) [National Collection of Micro-organism Cultures], InstitutPasteur, 28, rue du Dr Roux, 75724 Paris Cédex 15, France, on Jul. 22,1998, where it is publicly accessible under number I-2054. It was alsodeposited at the Deutsche Sammiung von Mikroorganismen und ZellkulturenGmbH (DSMZ) [German Collection of Micro-organisms and Cell Cultures],Mascheroder Weg 1b. D-38124 Braunschweig, Germany, on Jul. 13, 1998,where it is publicly accessible under number DSM 12295. This strainconstitutes one of the subjects of the invention.

Pure culturing of Pseudmonas sp I-2054 (or DSM 12295), which constitutesanother aspect of the present invention, may be carried out in a Petridish incubated at a temperature of between 25° C. and 30° C., and moreparticularly of between 25° C. and 28° C., for approximately 24 hours.

The nitrogen and carbon sources assimilable by Pseudomonas sp I-2054 (orDSM 12295) may be selected from glucose, fructose, galactose, trehalose,mannose, melobiose, sucrose, raffinose, maltotriose, maltose, lactose,lactulose, methyl-β-galactopyranoside, methyl-α-galactopyranoside,cellobiose, gentobiose, methyl-β-D-glucopyranoside,methyl-α-D-glucopyranoside, esculin, ribose, arabinose, xylose,palatinose, rhamnose, fucose, melezitose, D(+)-arabitol, L(−)-arabitol,xylitol, dulcitol, tagatose, glycerol, myo-innositol, mannitol,maltitol, turanose, sorbitol, adonitol, lyxose, erythritol,D(−)-tartrate, D(+)-malate, L(−)-malate, cis-aconitate, trans-aconitate,2-keto-D-gluconate, N-acetylglucosamine, quinate, betaine, succinate,fumarate, glycerate and glucosamine.

Among the possible maintenance media for the strain, the maintenancemedium of the type Difco MY agar (reference 0712-01-8) is considered tobe particularly advantageous. Said Difco MY agar medium has thefollowing composition:

bacto-yeast extract 3 g malt extract 3 g bacto-peptone 5 gbacto-dextrose 10 g bacto-agar 20 g

For conserving the strain, it is preferable to provide at least onepreculturing step. By a preculturing step is meant a step which consistsin developing and multiplying the bacterial strain without producingpolysaccharide.

It has been possible to demonstrate that, in general, theheteropolysaccharide (HP) comprises units of glucose and/or itsderivatives, galactose and/or its derivatives, mannuronic acid and/orits salts, and acetic acid and/or its salts.

The constituent units of the heteropolysaccharide (HP) are generallypresent in the following molar proportions, taking, as a reference,galactose as equal to 1:

glucose and/or its derivatives: 0.2–5,

mannuronic acid and/or its salts: 0.2–5,

acetic acid and/or its salts: 0–10.

More particularly, said units are present in the following molarproportions, taking, as a reference, galactose as equal to 1:

glucose and/or its derivatives: 0.5–4, and preferably 0.8–2,

mannuronic acid and/or its salts: 0.5–4, and preferably 0.8–2,

acetic acid and/or its salts: 0–8, and preferably 0–6.

The mannuronic and acetic acids may be present in the form of salts. Assalts, mention may be made of sodium, potassium, calcium or ammoniumsalts.

The principle of the methods of analyzing the heteropolysaccharide (HP)which have allowed its empirical formula to be determined as specifiedabove is the determination of the constituent elements (monosaccharidesand acids) after hydrolysis of said heteropolysaccharide (HP) andchromatographic assays with internal or external calibration.

Thus, the monosaccharide assay was carried out as follows:

100 mg of heteropolysaccharide (HP) are hydrolyzed in hermetic tubeswith 5 ml of molar trifluoroacetic acid at 105° C. from 3 to 6 hours.

This operation is followed by evaporation to dryness and takeup of thedry residue in 5 ml of pyridine containing 15 mg of sorbitol as internalstandard; then silylation on 1 ml of pyridine solution with 0.9 ml ofhexamethyldisilazane. The silylation is catalyzed by 0.1 ml oftrifluoroacetic acid.

The monosaccharides are then assayed by gas chromatography with F.I.D.(Flame Ionization Detection) on a glass capillary column with a lengthof 25 meters and a diameter of 0.25 mm, packed with methylsilicone phasehaving a film thickness of 0.14 microns. The carrier gas used ishydrogen, with a flow rate of 2 ml/minute.

The acetic acid is assayed following hydrolysis of 100 mgheteropolysaccharide (HP) with 5 ml of 2 N hydrochloric acid at 105° C.for one hour. Then 5 ml of a 5 mg/ml solution of propionic acid areadded as internal standard and the mixture is made up with 15 ml ofdemineralized water. The assay is carried out by HPLC using a 5 micronC-18 grafted silica column with a length of 250 cm and a diameter of 4.6mm. The eluent is a 0.02 mol/l aqueous phosphoric acid solution at aflow rate of 1.2 ml/minute. Detection is by refractometry.

The mannuronic acid is assayed by way of the CO₂ released bydecarboxylation following hot treatment of the gum with hydrochloricacid in accordance with the method described in the Food Chemical Codex,4th Edition, page 768.

The molar mass by weight is determined by exclusion chromatography onTSK PW 4000 and 6000 columns in series (columns with a length of 30 cmand a diameter of 7 mm), with refractometric detection. The eluent is a0.1 mol/l sodium nitrate solution. The concentration of theheteropolysaccharide in the eluent is approximately 0.015% by weight.Calibration is carried out using pullulans, which are monodispersepolysaccharides with molar masses of between 5×10³ and 1.6×10⁶ g/molextrapolated up to 10⁷ g/mol.

The weight-average molar mass (Mw) is obtained from the massdistribution curve obtained from the chromatogram; it is generallybetween 1×10⁵ and 8×10⁶ g/mol, preferably between approximately 8×10⁵and 5×10⁶ g/mol.

More particularly, (HP) has a weight-average molar mass (Mw) of betweenapproximately 2.5×10⁶ and 4×10⁶ g/mol inclusive.

As already mentioned, the (HP) has very good rheological properties insolution, especially in distilled water or mains water.

Thus, it has been found that, for example, 0.5% weight/weight solutionsof (HP) in distilled water at 23° C., and at a frequency of 1 Hz, giveG′ values of between 0.1 and 200 Pa and G″ values of between 0.1 and 20Pa.

(HP) gives strong or true gels when the G′ and G″ values areadvantageously between 20 and 200 Pa for G′ and between 0.5 and 15 Pafor G″. More advantageously still, G′ is between 20 and 150 Pa and G″ isbetween 0.5 and 10 Pa. In one particularly preferred embodiment, thevalue of G′ is approximately 100 Pa and that of G″ is approximately 5 Pa(in distilled water).

The (HP) gives the aqueous medium viscosity, which is evaluated by flowrheology. The rheological measurements of flow viscosity are carried outusing a controlled stress rheometer or controlled shear rate rheometer,such as, for example, using a viscometer of the RHEOMAT® or CARRIMED®type, respectively.

In both cases, the instrument measures the stress under flow of theHP+water mixture when this mixture is irreversibly strained. The flowviscosity is calculated from the stress.

This instrument therefore makes it possible to quantify the viscositylevel at a given shear rate.

The flow viscosity may be more simply evaluated with the aid of aBROOKFIELD® viscometer.

These rheological measurements of (HP) flow viscosity make it possible,moreover, to evaluate the flow threshold of the (HP) solution and/or ofthe formulation comprising it. Said threshold represents the force whichmust be provided in order to destroy the structure of the medium and toforce it to flow.

The flow rheology also makes it possible to quantify the ease with whichan (HP) solution and/or a formulation comprising it flows when thecontrolled shearing increases (pseudoplastic or shear-thinningbehavior).

It has been found, for example, that 1% weight/weight solutions of HP indistilled water containing 0.5% weight/weight of NaCl, at 23° C., giveflow viscosity values, at a shear rate of 0.1 s⁻¹, of between 100 and 5000 Pa·s, and more particularly between 200 and 2 000 Pa·s.

Under similar conditions, at a shear rate of 10 s⁻¹, of between 0.5 and300 Pa·s, and more particularly between 5 and 150 Pa·s.

These flow rheology data are representative of the behavior of theformulation when it is masticated, when it is transferred from onevessel to another, when it is expanded, etc.

The gels obtained by incorporating (—HP) into the medium areself-healing gels; in other words, after shearing, even strong shearing,the “fractured” gels have the ability to reform and to recover theirinitial properties.

The self-healing ability of the gels obtained from (HP) is evaluatedusing compression measurements carried out, for example, on an ETIA T2texturizer composed of a cylindrical measuring body 12.7 mm in diameter,with a penetration rate of 0.05 mm/s, and a penetration height of 15 mm.The plunger is pushed into the gel at the same place a number of times,at different intervals of time, and the compression force is recorded. Adetermination is made of the slope at the origin, expressed in mN/mm,which is representative of the elasticity of the gel.

For example, a gel is prepared with 0.5% weight/weight of (HP) indistilled water. This gel is then stored for 24 hours before thecompression measurements are carried out, either at room temperature(approximately 25° C.) or in the cold, at approximately 6° C.

Compression measurements are carried out at various intervals of time:0, 5, 15 minutes and 24 hours, with a 5-minute gap between eachmeasurement.

Thus, the slope remains constant is approximately equal to 45±1 mN/mm,irrespective of the measurement time (t=0.5, 15 minutes and 24 hours).

This indicates that the elasticity of the gel is stable and that it hasthe ability to self-heal a number of times in succession over time,while maintaining the same gel strength.

The present invention also provides a process for preparing theheteropolysaccharide (HP) as defined above.

The preparation process consists firstly in fermenting a mediumcomprising at least one carbon source assimilable by a Pseudomonas spI-2054 (or DSM 12295) strain, one of its recombinants or one of itsmutants.

Besides said assimilable carbon source, the fermentation medium may alsoinclude at least one organic or inorganic nitrogen source and, whereappropriate, one or more mineral salts.

The medium is inoculated conventionally with the Pseudomonas I-2054 (orDSM 12295) strain.

As an organic carbon source which is a constituent of the fermentationmedium, besides the abovementioned sugars, mention may also be made ofsugars such as starch, advantageously hydrolyzed, starch hydrolysates,mixtures of these sugars, and mixtures comprising at least one of thesesugars.

More particularly, mention may be made of glucose, sucrose, starch,advantageously hydrolyzed, starch hydrolysates, lactose, mixtures ofthese sugars, and mixtures comprising at least one of these sugars.Glucose and sucrose are the sugars which are still more preferred.

The carbon source concentration in the fermentation medium may bebetween 1 and 100 g/l, and preferably between 15 and 60 g/l.

As the organic nitrogen source, mention may be made of casein andcaseinates, fish hydrolysates, wheat, corn or soya flours, yeastextracts (baker's yeast, brewer's yeast, lactic yeasts, etc.), cornsteep liquor (CSL), urea, and potato proteins.

As inorganic nitrogen sources, mention may be made of ammonium or sodiumnitrates, and ammonium phosphates or sulfates.

The fermentation may also take place with a mixture of organic andinorganic nitrogen sources.

The nitrogen source concentration (organic, inorganic, or a mixture ofboth) in the fermentation medium may be between 1 and 80 g/l, andpreferably between 3 and 50 g/l.

The fermentation medium advantageously comprises calcium, alone or,where appropriate, in a mixture with other trace elements, such as iron,manganese and/or magnesium, and also vitamins and nucleotides.

The calcium may be introduced into the medium in the form of acomposition or compound which is inorganic or organic, such as CSL, soyaflour, or phosphate, nitrate, carbonate or sulfate salts, for example.

The fermentation may be carried out at pressures of between 1 and 4 barat a temperature of between 25° C. and 35° C., preferably between 25° C.and 30° C., under aerobic conditions.

The pH of the fermentation medium may be between 5 and 9, and preferablybetween 6 and 8. The pH may be adjusted, where appropriate, with a basesuch as sodium hydroxide, potassium hydroxide or aqueous ammonia, orwith an acid such as sulfuric acid, phosphoric acid, hydrochloric acidor nitric acid.

The fermentation medium, placed in a fermentation tank or container, maybe advantageously subjected to agitation. This agitation may be carriedout, for example, using a reciprocal shaker, a rotary shaker, a stirringspindle or a column of bubbles. The fermentation time is conventionallylonger than 30 hours, but generally between 40 and 100 hours.

The fermentation yields are generally greater than 40%, moreparticularly between 55 and 75%, and most particularly between 60 and75% by weight of heteropolysaccharide (HP) produced with respect to thecarbon source used.

After fermentation, the heteropolysaccharide (HP) may be separated fromthe fermentation must by the following steps:

i—the end-of-fermentation must is subjected to a heat treatment atbetween 80° C. and 120° C. for approximately 10 to 60 minutes,

ii—the heteropolysaccharide (HP) is precipitated by means of an at leastpartly water-miscible organic liquid,

iii—the heteropolysaccharide (HP) is separated from the organic liquid.

In step (i), the fermentation must containing the heteropolysaccharide(HP) is advantageously heated at temperatures of between 80° C. and 120°C. for 10 to 60 minutes, and preferably for between 15 and 45 minutes.

The must subjected to the heat treatment above advantageously has a pHof between 6 and 8.

However, this pH may be adjusted if necessary, where appropriate, with abase or an acid.

The latter may be chosen from the bases and acids mentioned above, usedfor adjusting the pH of the fermentation medium.

According to one preferred variant of the invention, the must obtainedfrom step (i) is held at the same temperature as the temperature of theheat treatment.

In step (ii), the heteropolysaccharide (HP) is recovered from the mustobtained in step (i), advantageously by precipitation using an organicliquid which is at least partly water-miscible and in which theheteropolysaccharide (HP) is insoluble or virtually insoluble.

By way of liquids which are suitable according to the present invention,mention may be made of acetone or alcohols containing from 1 to 6 carbonatoms, such as ethanol, propanol, isopropanol, butanol, tert-butanol, orthe mixture thereof.

More particularly, the precipitation of (HP) is carried out withisopropanol.

The volume of organic liquid used is generally at least twice that ofthe volume of must to be treated.

The precipitation of the heteropolysaccharide (HP) with an organicliquid may also be performed in the presence of salts, such as sodium,potassium or calcium sulfates, chlorides or phosphates.

According to one particular embodiment, the precipitation may take placeat a temperature of between 40 and 60° C.

The heteropolysaccharide (HP), once precipitated, may then be separated,in step (iii), from the organic liquid.

The separation method is not critical in itself, and may be selectedarbitrarily from the usual known separation methods, such as filtration,centrifugation or suction filtering, for example.

The fibers obtained may be optionally dehydrated, for example usingacetone or an alcohol such as ethanol, propanol or isopropanol.

The weight of alcohol required to carry out this dehydration operationis generally from 1 to 10 times that of the fibers to be treated.

The dehydrated fibers may undergo further filtration, centrifugation orsuction filtering operations.

Where appropriate, the fibers may be dried, ground and/or sieved so asto give a heteropoly-saccharide (HP) powder.

If the desire is to obtain a purer powder, it is possible to treateither the fermentation must or an aqueous solution reconstituted fromthe powder obtained according to the process described above, using oneor more enzymes.

By way of enzymes which may be suitable for this purpose, mention may bemade of proteases, mutanases, lipoproteases, cellulases and chitinases.

The enzymatic purification may be combined with or replaced by physicalpurification processes, such as the various filtration, centrifugationor dialysis methods, or various chromatographic techniques.

The fermentation musts and the reconstituted solutions ofheteropolysaccharide (HP), with or without having undergone purificationtreatment, may be concentrated.

Concentration may be advantageous in certain cases, in particular whenthe transport costs may thereby be decreased. In addition, theconcentrated solutions may be used more rapidly than theheteropolysaccharide (HP) powders.

Concentration may be carried out by all the techniques known to thoseskilled in the art, in particular evaporation, ultrafiltration ordiafiltration.

In the present invention, the heteropoly-saccharide (HP) isadvantageously present in the form of a solid of fiber or powder type.

As already mentioned, (HP) has very good rheological properties, and inparticular the ability to form true gels. Depending on the fermentationconditions, in particular depending on the components and theirconcentrations in the culture medium, and/or the precipitationconditions in step (ii) of the process (more particularly whether or notthe precipitation takes place in the presence of salts), (HP) has theadvantage of being able to be used as a thickener or as a gelling agent,or both.

Thus the present invention provides for the use of theheteropolysaccharide (HP) as described above or as obtained by theprocess defined above as a thickener and/or gelling agent.

(HP) may be used as a thickener and/or gelling agent, for example, inthe petroleum, agrochemical, food, cosmetics, paper and textileindustries, and also in paints, contact lenses, glues, inks andhousehold or industrial cleaners.

The amount of heteropolysaccharide (HP) of the invention which may beused in cosmetic compositions depends on the aqueous medium to bethickened and/or to be gelled. This amount may represent from 0.01% to5% approximately, preferably of the order of from 0.1% to 0.3%, of theweight of the thickened or gelled aqueous medium.

The term “cosmetic composition or formulation” is intended to mean allthe cosmetic products or preparations of the type(s) described in annex1 (“Illustrative list by category of cosmetic products”) of Europeandirective no. 76/768/EEC of Jul. 27, 1976, termed cosmetic directive.

The cosmetic compositions may be formulated into a large number of typesof products for the skin and/or the hair, such as mousses, gels (inparticular styling gels), conditioners, formulations for hair styling orfor facilitating the combing of hair, rinsing formulations, hand andbody lotions, products which regulate skin moisturization, cleansingmilks, makeup remover compositions, creams or lotions for protectionagainst the sun and ultraviolet radiation, beauty creams, antiacnepreparations, local analgesics, mascaras, products intended to beapplied to the lips or other mucosae, sticks, and other compositions ofthe same type.

These cosmetic compositions make use of a vehicle, or of a mixture oftwo or more vehicles, present in said compositions at concentrations ofbetween 0.5% and 99.5% approximately, generally between 5 and 90%approximately.

The choice of appropriate vehicle depends on the nature of theingredients used and on the destination of said compositions, dependingon whether the formulated product is supposed to be left on the surfaceto which it has been applied (for example, sprays, mousses, tonic lotionor gels) or, on the other hand, rinsed off after use (for example,shampoo, conditioner, rinsing lotions).

The aqueous vehicles present in the cosmetic compositions may alsocomprise C₁–C₆ alcohols, in particular methanol, ethanol andisopropanol. They may also comprise another solvent making it possibleto solubilize or disperse, in the aqueous medium, the variousingredients used in said compositions.

Said vehicles may thus also comprise a large variety of other solvents,such as acetone, hydrocarbons, halohydrocarbons, linalool, volatilesilicones and esters. The various solvents which may be used in theaqueous vehicles may be miscible or immiscible with each other.

When the cosmetic compositions are in the form of sprays, tonic lotions,gels or mousses, the preferential vehicles comprise, besides water,ethanol, volatile derivatives of silicone, and mixtures thereof.

The formulations for aerosol sprays and mousses may also include apropellant capable of generating the products in the form of a mousse orof fine, uniform sprays. By way of examples, mention may be made oftrichlorofluoromethane, dichloro-difluoromethane, difluoroethane,dimethyl ether, propane, n-butane or isobutane.

Said aqueous vehicles may take on a large number of forms, in particularthose of emulsions, including water-in-oil emulsions, oil-in-wateremulsions, and multiple emulsions, the desired viscosity of which mayrange up to 2 000 000 mPa·s.

Besides the aqueous vehicle, the cosmetic compositions may comprisesurfactants, used to disperse, emulsify, solubilize and stabilizevarious compounds used in particular for their emollient or humectantproperties. They may be of anionic, nonionic, cationic, zwitterionic oramphoteric type; by way of examples, mention may be made of:

anionic surfactants in an amount which may range from 3% to 50%,preferably from 5% to 20%, agents such as

-   -   alkyl ester sulfonates    -   alkyl sulfates    -   alkylamide sulfates    -   salts of saturated or unsaturated fatty acids

nonionic surfactants in an amount which may range from 0.1% to 30%,preferably from 2% to 10%, agents such as

-   -   polyoxyalkylenated alkylphenols    -   glucosamides, glucamides    -   glycerolamides derived from N-alkylamines    -   polyoxyalkylenated C_(8–C) ₂₂ aliphatic alcohols    -   the products resulting from the condensation of ethylene oxide        with a hydrophobic compound resulting from the condensation of        propylene oxide with propylene glycol,    -   amine oxides    -   alkylpolyglycosides and their polyoxyalkylenated derivatives    -   amides of C_(8–C) ₂₀ fatty acids    -   ethoxylated fatty acids    -   ethoxylated amidoamines, amines, amides

amphoteric and zwitterionic surfactants in an amount which may rangefrom 0.1% to 30%, preferably from 1% to 10%, agents such as

-   -   those of betaine type such as        -   betaines        -   sulfobetaines        -   amidoalkylbetaines        -   and sulfobetaines    -   alkylsultaines    -   products of condensation of fatty acids and of protein        hydrolysates,    -   cocoamphoacetates and cocoamphodiacetates    -   alkylampho-propionates or -dipropionates,    -   amphoteric derivatives of alkylpolyamines

Conditioners may also be present, in an amount which may range from0.05% to 5%, preferably from 0.1% to 1%.

Among these, mention may be made of those of synthetic origin which arebetter known under the name poly-quaternium, such as polyquaterniums −2,−7 and −10, cationic derivatives of polysaccharides, such ashydroxyethyl cocodimonium cellulose, guar hydroxypropyl trimoniumchloride, hydroxypropyl guar hydroxypropyl trimonium chloride,nonvolatile derivatives of silicones, such as amodimethicone,cyclomethicones, non-water-soluble and nonvolatile organopolysiloxanes,such as oils, resins or gums such as diphenyldimethicone gums.

The cosmetic compositions may also comprise polymers with film-formingproperties which may be used to provide a fixative function. Thesepolymers are generally present at concentrations of between 0.01 and10%, preferably of between 0.5 and 5%. They are preferably of the typeof polyvinylpyrrolidone, copolymers of polyvinylpyrrolidone and methylmethacrylate, copolymers of polyvinylpyrrolidone and vinyl acetate,polyethylene glycol terephthale/-polyethylene glycol copolymers, andsulfonated terephthalic copolyester polymers.

The cosmetic compositions may also comprise polymeric derivatives whichexert a protective function, in amounts of the order of 0.01–10%,preferably approximately 0.1–5% by weight; derivatives such as

-   -   cellulose derivatives    -   polyvinyl esters grafted onto polyalkylene backbones    -   polyvinyl alcohols    -   sulfonated terephthalic copolyester polymers    -   ethoxylated monoamines or polyamines, polymers of ethoxylated        amines

The performances of the cosmetic compositions may also be improved byusing plasticizers, in an amount which may range from 0.1 to 20% of theformulation, preferably from 1 to 15%. Among these agents, mention maybe made of adipates, phthalates, isophthalates, azelates, stearates,silicone copolyols, glycols, castor oil, or mixtures thereof.

It is also possible advantageously to add to these compositionsmetal-sequestering agents, more particularly those which sequestercalcium, such as citrate ions, or polymeric dispersants in an amount ofthe order of 0.1–7% by weight, in order to control the calcium andmagnesium hardness; agents such as

-   -   water-soluble salts of polycarboxylic acids    -   polyethylene glycols with molecular masses of the order of 1 000        to 50 000.

It is also possible to incorporate into the cosmetic compositionshumectants; mention may be made of glycerol, sorbitol, urea, collagen,gelatin, and emollients which are generally selected fromalkylmono-glycerides and alkyldiglycerides, triglycerides such as oilsextracted from plants and from vegetables or oils of animal origin orthe hydrogenated derivatives thereof, mineral oils or liquid paraffins,diols, fatty esters, and silicones.

To these compounds, it is possible to add, in combination, inorganicparticles or powders such as calcium carbonate, inorganic oxides inpowder form or in colloidal form such as titanium dioxide, silica,aluminum salts, kaolin, talc, clays and derivatives thereof.

One or more fragrances, colorants and/or opacifiers such as pigments aregenerally added to these ingredients.

In order to protect the skin and/or hair against attack from the sun andfrom UV rays, it is possible to add to these formulations sunscreenswhich are either chemical compounds which strongly absorb UV radiation,or inorganic particles, such as zinc oxide, titanium dioxide or ceriumoxides.

Preservatives, such as p-hydroxybenzoic esters, sodium benzoate or anychemical agent which prevents bacterial proliferation or theproliferation of molds and which is conventionally used of the cosmeticcompositions, are generally introduced into these compositions at alevel of from 0.01 to 3% by weight.

Agents which modify the activity of water and which greatly increaseosmotic pressure, such as carbohydrates or salts, may sometimes be used.

The cosmetic composition may also comprise other viscosity-modifyingand/or gelling polymers, such as crosslinked polyacrylates,hydrocolloids obtained by fermentation, such as xanthan gum andRheozan®, cellulose derivatives such as hydroxypropylcellulose orcarboxymethylcellulose, guars and the derivatives thereof, etc., usedalone or in combination.

The invention provides more particularly for the use of theheteropolysaccharide as a thickener and/or gelling agent in foodformulations.

The food formulations to which the heteropolysaccharide (HP) is addedare conventionally simple or multiple liquid emulsions, complex gas andliquid emulsions (expanded systems), suspensions of liquids and solids,or any other system combining these possibilities.

In these formulations, the liquid is advantageously water or a liquidcomprising water, at least in part.

The food formulations are obtained by implementing the conventionalmethods for preparing food formulations according to their type. Thus,the (HP), advantageously in the form of a solid of fiber or powder type,is mixed with the other ingredients required for the formulation. Theentire mixture may, where appropriate, be homogenized.

The temperature at which the formulation is prepared is not critical initself. The formulations comprising the (HP) may be sterilized withoutany damage to their service properties. Another advantage of (HP) isthat it is possible to prepare the food formulations without having toheat the ingredients beforehand.

(HP) remains compatible despite the diversity of the food formulations(pH, ionic strength, composition), and substantially retains itsproperties.

The advantageous rheological properties associated with theheteropolysaccharide (HP) which is the subject of the invention, andalso the capacity of the latter to give true gels at temperatures lowerthan or equal to 40° C., and to do so within a wide pH range, also makesit possible to impart to the formulations in which it is used, alone orin combination with other additives, a texture close to that offormulations comprising exclusively said additives.

The measurable parameters for characterizing the texture of the foodformulations are rheological in nature, and consist essentially inmeasuring the elastic (G′) and viscous (G″) moduli, and the flowviscosity at a given shear rate. G′ and G″, and also the viscosity, havebeen defined above.

The objective of these rheological characteristics is to demonstrate theviscoelastic and/or pseudoplastic behaviors of the formulations, inorder to compare them with each other.

(HP), advantageously in the form of a solid of fiber or powder type, hasthe capacity to impart a shear-thinning profile to the formulationcomprising it.

(HP) has, similarly, the capacity to give true gels which are able toself-heal after application of a mechanical stress.

It should be noted that the G′ and G″ moduli, and also the viscosity,measured for a formulation may be different from those measured for (HP)in distilled water.

In milk-based and set-desserts, such as, for example, flans, it ispossible advantageously to replace, at least partially, the usualgelling agents, in particular gelatin, by (HP).

In salty-acid media, such as vinaigrettes, the aqueous medium presentmay be structured by adding small amounts of (HP).

In the field of confectionery, in particular in jellied candies of theHARIBO® type, it is possible advantageously to replace, at leastpartially, the gelling agents, such as gelatin for example, by (HP).

In media with high ionic strength, in particular in pigmeat products,(HP) may be added to the carrageenans in order to reinforce the texture,in particular the elastic appearance of sausages, for example.

In formulations intended to be expanded, such as Chantilly creams,toppings or ice creams, (HP) may be used as a thickener and/or gellingagent.

Similarly, (HP) may be used in formulations such as mayonnaises,vegetable mousses or mousses containing proteins, for instance meat orfish mousses, or mousses containing albumin, such as meringues.

As a thickener and/or gelling agent, (HP) may also be part of thecomposition of yogurts.

In the abovementioned food applications, use is made in general of from0.01 to 5% by weight, and preferably between 0.05 to 2% by weight, ofheteropolysaccharide (HP) relative to the weight of the composition orformulation which comprises it. More preferably still, from 0.1 to 1% byweight of heteropolysaccharide (HP) is used in relation to the weight ofthe composition or formulation.

It should be noted that the heteropolysaccharide (HP) does not alter thetaste of the foods into which it is introduced.

The invention finally provides the food compositions or formulationscomprising the heteropolysaccharide (HP) as defined above.

The following examples illustrate the present invention without,however, limiting its scope.

EXAMPLES Example 1

This example describes the pure culturing of Pseudomonas sp I-2054 (orDSM 12295), and the conditions under which the strain is conserved.

Pure culturing of Pseudomonas sp I-2054 (or DSM 12295):

The medium for maintaining the Pseudomonas sp I-2054 (or DSM 12295)strain is Difco MY agar medium (reference 0712-01-8). The composition ofthis medium, already made up, is:

bacto-yeast extract 3 g malt extract 3 g bacto-peptone 5 gbacto-dextrose 10 g bacto-agar 20 g

21 g of this medium are diluted in one liter of distilled water. Afterdissolution, the medium is sterilized in an autoclave for 15 minutes at121° C. The medium is then distributed into Petri dishes.

Culturing is carried out on Petri dishes incubated at between 25° C. and30° C., preferably between 25° C. and 28° C., for a minimum of 24 hours.

Preculturing—Conservation:

The strain is then conserved in the form of a tube frozen at −196° C. bythe process of liquid nitrogen freezing (LNF).

For liquid nitrogen freezing (LNF) a preculture is prepared on PYG10medium having the following composition:

malt extract 3 g (obtained from Oxoïd) yeast extract 3 g (Oxoïd) soyapeptone 5 g (Oxoïd) glucose 10 g (obtained from Prolabo) mineral waterqs 1 l.

For preparing the medium, all the ingredients are dispersed in themineral water. The pH is adjusted to 6.5 with 10% H₂SO₄. The medium issterilized for 20 minutes at 120° C. in an autoclave.

After incubation for 24 hours at 28° C. on a rotary shaker at 220 rpmand amplitude=50 mm, 10% by volume of pure sterile glycerol are added tothe culture. The culture is then distributed into cryotubes withcapacities ranging from 1 ml to 10 ml, preferably from 2 ml to 4 ml.

These tubes are conserved in liquid nitrogen.

Example 2

This example describes the preparation and production of theheteropolysaccharide according to two fermentation processes, one withan organic nitrogen source and the other with an inorganic nitrogensource.

In this example, two “preculturing” steps are involved. These steps takeplace in 500 ml Erlenmeyer flasks, which corresponds to 100 ml ofmedium.

The production step, which corresponds to the step during which thebacterial strain produces the polysaccharide, takes place in a 20 literfermenter having a useful capacity of 15 liters.

The agitation conditions of the rotary shaker are: speed=220 rpm andamplitude=50 mm.

Preculturing Step 1:

Preculturing step 1 is carried out with a PYG 10 medium of the followingcomposition:

malt extract 3 g (Oxoïd) yeast extract 3 g (Oxoïd) bacto-peptone 5 g(Oxoïd) glucose 10 g (Prolabo) distilled water qs 1 l.

All the ingredients are dispersed in a quantity of distilled watersufficient for 1 l. The pH is adjusted, before sterilization, to 6.5with 10% H₂SO₄. The medium is sterilized for 20 minutes at 120° C. in anautoclave.

After sterilization and before inoculation with the cryotube (qs), thepH is at 7.33.

Each Erlenmeyer flask is seeded with a sufficient quantity of the LNF.

After incubation for 24 hours at 28° C. on a rotary shaker (220 rpm,A=50 mm), the medium has the following characteristics:

pH=6.50

viscosity<10 mPa·s

the population read on MY agar (Difco medium, reference 0712-01-8) after72 hours at 28° C.

=1.7×10⁵ cfu/ml.

After incubation for 24 hours, preculture 1 is used to seed preculture2.

Preculturing Step 2:

Preculturing step 2 is carried out with a medium of the followingcomposition:

yeast extract 4 g (Oxoïd) MgSO₄.7H₂O 0.8 g (Prolabo) FeSO₄.7H₂O 0.01 g(Prolabo) MnSO₄.H₂O 5 ppm Mn²⁺ (Prolabo) K₂HPO₄ 4 g (Prolabo) or Na₂HPO₄3 g (Prolabo) glucose 10 g (Prolabo) deionized water qs 1 l

A 100 g/l glucose solution is prepared in distilled water and thensterilized at natural pH for 15 minutes at 121° C.

The remainder of the ingredients is dispersed in a quantity of deionizedwater sufficient for 900 ml, and then adjusted to pH 6.8 beforesterilization for 15 minutes at 121° C.

After sterilization, 10 ml of the glucose solution are added to eachErlenmeyer flask.

After sterilization and before inoculation, the pH is 6.88.

Each Erlenmeyer flask is inoculated with the quantity sufficient forpreculture 1.

After incubation for 24 hours at 28° C. on a rotary shaker (220 rpm,A=50 mm), the medium has the following characteristics:

pH=6.82

viscosity=50–100 mPa·s

the population read on MY agar (Difco medium, reference 0712-01-8) after72 hours at 28° C.

=1.6×10⁹ cfu/ml.

After incubation for 24 hours, preculture 2 is used to seed the twofermentation media (fermenters 1 and 2) in the production step.

Production Step:

The final step is the heteropolysaccharide (HP) production step.

The medium of fermenter 1 has the following composition:

glucose 20 g (Prolabo) CSL (corn steep liquor) 6 g (Prolabo) MgSO₄.7H₂O0.8 g (Prolabo) MnSO₄.H₂O 5 ppm Mn²⁺ (Prolabo) K₂HPO₄ 1 g (Prolabo)antifoam 0.2 ml deionized water qs 1 lGlucose

the sufficient number of grams of glucose are dissolved in a quantity ofdeionized water sufficient for 3 l. The pH is lowered to 5 with 10%H₂SO₄. The solution is sterilized in a Mariotte flask for 30 minutes at120° C. in an autoclave. Nitrogen+salts

the sufficient number of grams of corn steep liquor (CSL), 15 g ofK₂HPO₄, 12 g of MgSO₄·7H₂O, 23 ml of a 10 g/l solution of MnSO₄·H₂O and3 ml of antifoam are dissolved in a quantity of deionized watersufficient for 7 l. The pH is adjusted to 6.5 with 10% H₂SO₄. Thismixture is sterilized in situ for 30 minutes at 120° C. 1 N sodiumhydroxide

40 g of NaOH pellets are dissolved in a quantity of distilled watersufficient for 1 l. The solution is sterilized in a Mariotte flask for30 minutes at 120° C. in an autoclave.

When all the ingredients are at 28° C., they are mixed in the fermenter.The fermenter is then inoculated with the qs of preculture 2.

The fermentation conditions in fermenter 1 are as follows:

Agitation

200 rpm from 0 to 20 hours old, then 400 rpm until the end offermentation.

Aeration

400 l/h from 0 to 18 hours, and then 825 l/h from 24 hours until the endof fermentation.

The temperature is regulated at 28° C.

The pH is regulated at 6.8 with 1 N NaOH.

The pressure is atmospheric pressure.

The medium of fermenter 2 has the following composition:

NaNO₃ 1.2 g (Prolabo) NH₄NO₃ 0.25 g (Prolabo) CaSO₄.2H₂O 0.3 g (Prolabo)MgSO₄.7H₂O 0.8 g (Prolabo) MnSO₄.H₂O 5 ppm Mn²⁺ (Prolabo) FeSO₄.7H₂O0.01 g (Prolabo) Na₂HPO₄ 3 g (Prolabo) glucose 45 g (Prolabo) antifoam0.2 ml demineralized water qs 1 lGlucose

the sufficient number of grams of glucose are dissolved in a quantity ofdeionized water sufficient for 3 l. The pH is adjusted to 5 with 10%H₂SO₄. The solution is sterilized in a Mariotte flask for 30 minutes at120° C. in an autoclave.Nitrogen+salts

18 g of NaNO₃, 3.75 g of NH₄NO₃, 4.5 g of CaSO₄·2H₂O, 23 ml of a 10 g/lsolution of MnSO₄·H₂O, 12 g of MgSO₄·7H₂O, 75 ml of a 2 g/l solution ofFeSO₄·7H₂O, 4.5 g of Na₂HPO₄ and 3 ml of antifoam are dissolved in aquantity of demineralized water sufficient for 7 l. The pH of thissolution is adjusted to 6 with 10% H₂SO₄. This mixture is sterilized insitu for 30 minutes at 120° C. 1 N sodium hydroxide

40 g of NaOH pellets are dissolved in a quantity of distilled watersufficient for 1 l. The solution is sterilized in a Mariotte flask for30 minutes at 120° C. in an autoclave.

When all the ingredients are at 28° C., they are mixed in the fermenter.The fermenter is then inoculated with the sufficient quantity ofpreculture 2.

The fermentation conditions in fermenter 2 are as follows:

Agitation

200 rpm from 0 to 20 hours old, then 400 rpm until the end offermentation.

Aeration

400 l/h from 0 to 24 hours, and then 825 l/h from 24 hours until the endof fermentation.

The temperature is regulated at 28° C.

The pH is regulated at 6.8 with 1 N NaOH.

The pressure is atmospheric pressure.

Fermentation Results:

Depending on the culture medium studied, the fermentation times rangefrom 60 to 115 hours, the solids which may be precipitated withisopropanol range from 10 to 18 g/kg and the weight yield with respectto the carbon source used ranges from 44 to 70%.

Extraction and Purification:

The end-of-fermentation must is stabilized with 10% (weight/weight) ofpure IPA. It is then heat-treated at 100–110° C. for 20 minutes at pH 7.The pH, during the heat treatment, does not vary.

On emergence from the heat treatment, the must is extracted while hot(temperature>70° C.).

The precipitation conditions are:

1.7 kg of hot must in 4.5 kg of pure IPA (at approximately 50° C.).

After precipitation, the fibers are chopped up and then washed anddehydrated with IPA having a titer of 78%.

The fibers are then dried in a ventilated oven at approximately 85° C.until a product is obtained which has a moisture content ofapproximately 10% by weight.

The fibers are then ground and sieved.

The analysis of the units of the heteropolysaccharide obtained in themedium of fermenter 1 (organic medium) is as follows in molarproportions (percentage by mass):

galactose 1 (13%) glucose 1.08 (14%) mannuronic acid 1.1 (17%) aceticacid 4.3 (18.6%)

The analysis of the units of the heteropolysaccharide obtained in themedium of fermenter 2 (inorganic medium) is as follows (percentage bymass):

galactose (22.5%) glucose (21.7%) mannuronic acid (26%) acetic acid(31%)

Example 3

The subject of this example is the use of (HP) obtained in example 2 ina food formulation for topping.

In the examples which will follow, the flow viscosities, expressed inmPa·s, were measured using a BROOKFIELD RVT 20-2 viscometer at roomtemperature.

The values of the elastic moduli, expressed in Pa, were produced using aCARRIMED CSL 100 controlled stress rheometer. They were measured in anoscillatory system—frequency from 0.01 to 10 Hz.

The measurements of degree of expansion, expressed in %, were carriedout as follows:

-   -   the mousse is introduced into a beaker of known volume (V) and        of known mass, the beaker is given three sharp taps, and the        mousse is leveled;    -   the beaker is weighed in order to determine the mass (M) of        mousse that it contains;    -   the degree of expansion=[M(g)/V(ml)]×100

Two formulations are prepared:

formulation 3.1: comprising the heteropolysaccharide (HP) according tothe invention,

formulation 3.2 (comparative): comprising sodium caseinate and sodiumalginate.

The compositions of the formulations are summarized in table I.

TABLE I Formulation 3.1 Formulation 3.2 Components (% by weight) (% byweight) Oily phase Hydrogenated palm 7.6 7.6 oil Monodiglyceride 0.760.76 acetic ester Monodiglyceride 0.76 0.76 lactic ester Aqueous phaseSugar 8.35 8.35 Powdered skimmed 7.44 7.44 milk Maltodextrin 4.6 4.6(Glucidex ® 19) Sodium caseinate — 1.5 Sodium alginate — 0.02Heteropoly- 0.5 — saccharide (HP) Water qs 100 qs 100Aqueous Phase:

In a beaker equipped with a deflocculating paddle, the amount of waterrequired is weighed out and the mixture of powders described in thetable above is dispersed with vigorous stirring (500 rpm).

The stirring is maintained for 5 minutes after said powders have beenintroduced.

Oily Phase:

In a beaker, the fatty substance and the emulsifiers are heated, in awater bath, to 70° C.

The oily phase is then added to the aqueous phase with stirring at 1 000rpm.

The stirring is maintained for 5 minutes after the oily phase has beenintroduced. During this operation, the water evaporation is compensated.

The entire mixture is then homogenized using an Ultra-Turrax for 2minutes at 20 000 rpm.

The mixture is cooled to a temperature lower than 10° C., beforecarrying out the expansion. This takes place using a laboratory mixer ofthe KENWOOD CHEF type, at maximum speed for 3 minutes at a temperatureclose to 5° C.

The results are collated in table II.

TABLE II Formulation Formulation 3.1 3.2 Viscosity before expansion 1500   1 700   (mPa · s) Degree of expansion (%) 350 250 G′ measured at 1Hz (Pa) 1 800   1 600   G″ measured at 1 Hz (Pa) 300 400

These results show that formulation 3.1, which uses the (HP) accordingto the invention, has a viscosity lower than that of comparativeformulation 3.2 and, because of this, is easier to expand.

In addition, formulation 3.1 (according to the invention) is firstlymore gelled (higher G′ at high frequency), and has an improved degree ofexpansion.

1. A heteropolysaccharide (HP) which is obtained by fermenting a mediumcomprising at least one Pseudomonas sp 1-2054 (or DSM 12295) strain, anda carbon source assimilable by said strain.
 2. The heteropolysaccharide(HP) as claimed in claim 1, which comprises units of glucose, galactose,and/or their derivatives, mannuronic acid, acetic acid, and/or theirsalts.
 3. The heteropolysaccharide (HP) as claimed in claim 2, whereinsaid units are present in the following molar proportions, taking, as areference, galactose as equal to 1: glucose and/or its derivatives:0.2–5, mannuronic acid and/or its salts: 0.2–5, acetic acid and/or itssalts: 0–10.
 4. The heteropolysaccharide (HP) as claimed in claim 1,wherein said units are present in the following molar proportions,taking, as a reference, galactose as equal to 1: glucose and/or itsderivatives: 0.5–4, mannuronic acid and/or its salts: 0.5–4, acetic acidand/or its salts: 0–8.
 5. The heteropolysaccharide (HP) as claimed inclaim 1, wherein mannuronic and acetic acid are present in the form ofsalts.
 6. The heteropolysaccharide (HP) as claimed in claim 1, which hasa weight-average molar mass (Mw) of between 1×10⁵ and 8×10⁶ g/mol. 7.The heteropolysaccharide (HP) as claimed in claim 1, which has aweight-average molar mass (Mw) of between approximately 2.5×10⁶ and4×10⁶ g/mol inclusive.
 8. The heteropolysaccharide (HP) as claimed inclaim 1, wherein 0.5% weight/weight solutions of saidheteropolysaccharide (HP) in distilled water at 23° C., and at afrequency of 1 Hz, give G′ values of between 0.1 and 200 Pa and G″values of between 0.1 and 20 Pa.
 9. The heteropolysaccharide (HP) asclaimed in claim 1, wherein 0.5% weight/weight solutions of saidheteropolysaccharide (HP) in distilled water at 23° C., and at afrequency of 1 Hz, give G′ values of between 20 and 200 Pa and G″ valuesof between 0.5 and 15 Pa.
 10. The heteropolysaccharide (HP) as claimedin claim 1, wherein 1% weight/weight solutions of said HP in distilledwater containing 0.5% weight/weight of NaCl, at 23° C., give flowviscosity values at a shear rate of 0.1 s⁻¹ of between 100 and 5 000Pa·s, and more particularly between 200 and 2 000 Pa·s.
 11. Theheteropolysaccharide (HP) as claimed in claim 1, wherein 1%weight/weight solutions of said HP in distilled water containing 0.5%weight/weight of NaCl, at 23° C., give flow viscosity values, at a shearrate of 10 s⁻¹, of between 0.5 and 300 Pa·s.
 12. A process for preparingthe heteropolysaccharide (HP) as defined in claim 1, wherein theheteropolysaccharide (HP) is separated from the fermentation must by thefollowing steps: i—the end-of-fermentation must is subjected to a heattreatment at between 80° C. and 120° C. for approximately 10 to 60minutes, ii—said heteropolysaccharide (HP) is precipitated by means ofan at least partly water-miscible organic liquid, iii—theheteropolysaccharide (HP) is separated from the organic liquid.
 13. Theprocess as claimed in claim 12, wherein in step (i) the must subjectedto the heat treatment has a pH of between 6 and
 8. 14. The process asclaimed in claim 12, wherein the must obtained from step (i) is held atthe same temperature as the temperature of the heat treatment.
 15. Theprocess as claimed in claim 12, wherein in step (ii) the precipitationof the heteropolysaccharide (HP) with an organic liquid is performed inthe presence of salts, comprising sodium, potassium or calcium sulfates,chlorides or phosphates.
 16. The process as claimed in claim 12, whereinin step (ii) precipitation takes place at a temperature of between 40and 60° C.
 17. An isolated Pseudomonas sp strain deposited at the CNCMunder number I-2054 and also at DSMZ under number DSM
 12295. 18. A pureculture of Pseudomonas sp I-2054 (or DSM 12295).
 19. A thickener and/orgelling agent comprising the heteropolysaccharide (HP) as claimed inclaim
 1. 20. A food formulation comprising the heteropolysaccharide (HP)as claimed in claim 1 in amounts of between 0.01 to 5% by weight as athickener and/or gelling agent.
 21. A method to obtain gels withoutadding additional cations to the medium comprising using theheteropolysaccharide (HP) as claimed in claim
 1. 22. A composition orformulation comprising the heteropolysaccharide (HP) as described inclaim 1 and a carrier.
 23. A heteropolysaccharide (HP) which is obtainedby fermenting a medium comprising at least one recombinant or one mutantof Pseudomonas sp I-2054 (or DSM 12295) strain, and a carbon sourceassimilable by said recombinant or said mutant, which comprises units ofglucose, galactose, and/or their derivatives, mannuronic acid, aceticacid, and/or their salts, wherein said units are present in thefollowing molar proportions, taking, as a reference, galactose as equalto 1: glucose and/or its derivatives: 0.2–5, mannuronic acid and/or itssalts: 0.2–5, acetic acid and/or its salts: 0–10, which has aweight-average molar mass (Mw) of between approximately 1×10⁵ and 8×10⁶g/mol inclusive.
 24. A thickener and/or gelling agent comprising theheteropolysaccharide (HP) as claimed in claim
 23. 25. A food formulationcomprising the heteropolysaccharide (HP) as claimed in claim 23 inamounts of between 0.01 to 5% by weight as a thickener and/or gellingagent.
 26. A method to obtain gels without adding additional cations tothe medium comprising using the heteropolysaccharide (HP) as claimed inclaim
 23. 27. A composition or formulation comprising theheteropolysaccharide (HP) as described in claim 23 and a carrier.